The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The HDA includes at least one disk (such as a magnetic disk, magneto-optical disk, or optical disk), a spindle motor for rotating the disk, and a head stack assembly (HSA). The spindle motor typically includes a rotatable spindle motor hub on which the disks are mounted and a stator. Rotation of the spindle motor hub results in rotation of the attached disks.
The HSA includes an actuator, at least one head gimbal assembly (HGA), and a flex cable assembly. A conventional “rotary” or “swing-type” actuator typically includes an actuator body. The actuator body has a pivot bearing cartridge to facilitate rotational movement of the actuator. One or more actuator arms extend from the actuator body. Each actuator arm typically supports one or two HGAs. An actuator coil is supported by the actuator body opposite the actuator arms. The actuator coil is configured to interact with one or more magnets, typically a pair, to form a voice coil motor (VCM). The PCBA controls current passing through the actuator coil that results in a torque being applied to the actuator. The flex cable assembly electrically couples the HSA to the PCBA, and carries the current to the actuator coil.
Each HGA includes a head for reading and writing data from and to the disk. In an optical disk drive, the head will typically include a mirror and objective lens for reflecting and focusing a laser beam on to a surface of the disk. In magnetic recording applications, the head will typically include a transducer having a writer that may be of a longitudinal or perpendicular design, and a read element that may be inductive or magnetoresistive. The flex cable assembly also carries the signals from/to the PCBA to/from the heads as the heads write and read information recorded in concentric circular tracks on the disks.
A latching mechanism is provided to facilitate latching of the actuator in a parked position when the heads are not being used to read from or write to the tracks of information on the disk. In the parked position, the actuator is positioned with the heads either at an inner diameter (ID) of the disk or at or beyond an outer diameter (OD) of the disk such as upon a ramp. A crash stop coupled to the disk drive base is provided to limit rotation of the actuator in a given direction. The crash stop is configured to contact a portion of the actuator when the actuator is rotated to an extreme rotational position in a given rotational direction. Another crash stop may be provided to limit actuator rotation in an opposite rotational direction. The latching mechanism may additionally function as one of the crash stops.
Disk drives are frequently used in small mobile electronic devices such as laptop and hand-held computing devices, audio devices, audio/video devices, and personal electronic organizers. In such applications there is an enhanced risk that the disk drive may be subject to mechanical shock events, for example when the host device is dropped. During a mechanical shock event, the disk drive base may experience significant rotational accelerations that can cause a sudden relative rotation of the actuator. Such a sudden relative rotation of the actuator may result in damage to the HSA, especially to its attached head gimbal assemblies. The adjacent disk surface(s) may also be damaged, which may result in loss of data. Various latch designs have attempted to secure the actuator during such mechanical shock events, but many such designs have proven to be complex, costly or unreliable. Accordingly, there is need in the art for an improved actuator latch configuration.